1. Technical Field
The present disclosure relates generally to equipment and procedures in the field of spinal surgery and, in exemplary implementations, to instruments, systems and methods for positioning and/or evaluating the positioning of pedicle screws in connection with orthopedic applications.
2. Background Art
Surgical techniques for spinal fixation vary widely in terms of the types of surgical equipment used, but modern surgical practice continues to rely quite heavily on the strength and stability afforded by the common pedicle screw. However, care must be taken during pedicle screw placement to protect against nerve damage. For example, after forming a pilot hole in the bone tissue of a pedicle but before moving forward with pedicle screw implantation, surgeons will typically take the opportunity to inspect the axially-extending side walls of the pilot hole to locate defects. With the advent and increasing use of minimally invasive surgical procedures that afford only a limited view with respect to anatomical structure, the risk of misplaced pedicle screws has increased. In the event a surgeon locates a breach of any significant size of the cortical bone adjacent the spinal column, he or she will mostly likely elect to redirect the screw to avoid the risk of complications such as pain, paralysis and hemorrhaging.
One method for locating such cortical breaches in regular use by surgeons is tissue palpation by means of the common tactile feeler probe. While surgeons are aware that this method has its limitations, including with regard to sensitivity in the case of relatively small breaches, as well as with regard to false positives, many if not most have become comfortable with the use of the tactile feeler probe. To the extent techniques and tools can be developed to facilitate continued effective use of tactile diagnostic techniques in the context of minimally invasive spinal surgical procedures, there is likely to be a strong market for same among current practitioners.
Recent developments in the use of ultrasound technology in surgical applications have shown promise. With the increasing miniaturization of electronics generally has come the ability to position ultrasound transducers to beneficial effect in increasingly smaller and, at least up until recently, harder to reach anatomical locations. Nevertheless, and despite efforts to date, a need remains for convenient, sanitary, low-cost, and effective equipment and related techniques for locating pilot hole bone tissue defects prior to pedicle screw implantation.
These and other needs are satisfied by the instruments, systems and methods disclosed herein, as will be apparent from the detailed description which follows, particularly when read in conjunction with the figures appended hereto.